Weather Tutorial Page 5a

After air begins to cool and then becomes saturated, sublimation or condensation starts the cloud-forming process. The air within the newly formed cloud layer is either stable or unstable. This stability or instability will determine the type of cloud structure. This is because stable air resists convection while unstable air prefers convection. Cloud formation in stable air develops horizontally in uniform, sheet-like layers called "strata". When an unstable layer of air is forced upward by convection, a cloud forms vertically. How high into the atmosphere the cloud shapes itself depends upon the depth of the unstable layer. These clouds tend to pile up in a heap or "cumulus." They are characterized by their lumpy, billowy shapes. Vertical heights of cumulus clouds vary from the shallow fair weather cumulus to the giant thunderstorm cumulonimbus clouds. The convection process occurring in unstable air will give a bumpy ride to an airplane passing through it. In stable air flying is usually smooth.

NASA Research
An Altair unmanned aerial vehicle (UAV) is pioneering climate and environmental research for NASA and the National Oceanic and Atmospheric Administration (NOAA).

This research program could be particularly valuable in predicting extended days of rain in time to mitigate natural disasters like floods and mudslides. Its sophisticated sensor suite includes a passive microwave radiometer that will be used to measure atmospheric rivers—air currents laden with moisture that sweep up from the tropics. These atmospheric rivers, flowing along polar cold front boundaries, can cause major floods on the U.S. west coast.

The Altair UAV Altair was developed to conduct high altitude scientific research and to perform flight operations in national air space. With a wingspan of 86 feet, it is designed for operations above 15,000 meters (50,000 feet).